Hepadnaviruses are small, hepatotropic DNA viruses that can persistently infect the liver of a variety of animal hosts, including humans, and cause disease. There is a close association between chronic HBV infection and the development of hepatocellular carcinoma (HCC). Active viral replication is necessary for HCC and other hepadnavirus-associated diseases. Although they have DNA genomes, hepadnaviruses replicate via reverse transcription of an RNA intermediate (RNA pregenome) resulting in a relaxed circular DNA genome. Integral to reverse transcription are the specific initiation or priming events leading to successful minus and plus strand DNA synthesis. The focus of the proposed research is understand the initiation and elongation of minus and plus strand DNA synthesis. This will be done by defining and characterizing the cis- acting elements on the genome involved in minus and plus strand DNA synthesis and by defining and characterizing the viral trans factors (the C and P proteins) that interact with these cis-acting elements during reverse transcription. Genetic and biochemical approaches will be undertaken to achieve our specific aims.